Numerical Investigation of Piezoresistive Materials and Sensor Geometry for Enhanced Sensitivity and Reduced Structural Nonlinearity in Microelectromechanical Systems Pressure Sensors for In Vivo Biomedical Applications

This paper presents a finite element analysis study on the impact of material selection and sensor geometry on the performance metrics of a microelectromechanical systems piezoresistive readout‐based pressure sensor for biomedical applications. The pressure sensor dimensions are designed for housing in a typical 5Fr catheter utilized for in vivo biomedical applications. In this work, focus is on devising a rational selection of piezoresistor material and sensor geometry for maximizing performance metrics of the sensor. For investigation, we have considered three generations of piezoresistive materials which exhibit a wide range of gauge factors. Subsequently, the study explores different sensor mechanical diaphragm geometries, focusing on stress distributions, displacements, and variations in resistance governing sensitivity and structural nonlinearity. Simulation results show that for constant resonant frequency and fixed piezoresistors, among the sensor geometries, circular geometry of sensor platform depicts the highest electrical sensitivity. Among piezoresistor materials, gold has the lowest sensitivity (1.229 × 10 ⁻⁴ ), confirming its weak piezoresistive nature. P‐type silicon demonstrates moderate sensitivity, reaching up to (6.779 × 10 ⁻⁴ ). On the other hand, response of graphene nanoplate SU‐8 is the highest (9.501 × 10 ⁻⁴ ). Results show that nonlinearity errors for square, octagonal, and circular geometries are −0.637%, −0.431%, and −0.420%, respectively, within a pressure range of 0–100 mmHg.